Toner having bi-layer or triple-layer

ABSTRACT

The present invention relates to a toner having a double- or triple-layered structure. The present invention is effective in that pigments and charge control agents are located most properly for the realization of high-resolution toners through addition and polymerization of hydrophilic monomers or polymers with the toners; the manufacture of high-resolution toners becomes very easy irrespective Lo the kind and amount of a wax used for polymerized toners by forming thin layers by using polar grafting agents; and long-term preservation is assured as well as the affect by moisture is minimized.

TECHNICAL FIELD

The present invention relates to a toner having a double- ortriple-layered structure with a superior weatherability. In more detail,the present invention relates to weatherproof toners having a double- ortriple-layered structure in which pigments and charge control agents arelocated most properly for the realization of high-resolution tonersthrough addition and polymerization of hydrophilic monomers or polymerswith the toners; the manufacture of high-resolution toners becomes veryeasy irrespective to the kind and amount of a wax used for polymerizedtoners by forming thin layers by using polar grafting agents; andlong-term preservation is assured as well as the affect by moisture isminimized.

BACKGROUND ART

Generally, toners are used for the development of electronicphotographs, electrostatic printers, copying machines, etc. and refer topigments used for the development of pictorial images in printedmaterials during the printing work. It has been the actual situationthat the demand for image-formation devices such as printers, etc. hasbeen increased rapidly, and consequently, the amount of use of tonershas been increased as the preparation for documents using computers andsimilar works has been generalized recently.

There are many methods of manufacturing toners. In the melting-mixingprocess, which is the most widely known general method, resins andpigments are put together, melted and mixed or extruded, and pulverizedand classified in order to manufacture toner particles. However, thetoner particles manufactured according to the above process have beenproblematic in their charging or flowing property since they have a widedistribution of particle sizes and very irregular shapes such as sharpedges, etc.

In order to resolve the above problem, methods of manufacturingspherical toner particles according to the polymerization method havebeen presented. As concrete methods by the above polymerization method,emulsion polymerization method and suspension polymerization method havebeen known. At present, the suspension polymerization is preferred sincethe emulsion polymerization is more complicated process.

The method of manufacturing toners by the suspension polymerization isdisclosed in the U.S. Pat. No. 6,337,169. What is claimed in this patentis that the pigment included in a wax forms pictorial images promptlywith the wax since the wax is melted promptly when the toner is fused ata high temperature if only the fixed part of a pigment is melted in thewax, thus enabling the formation of high-quality pictorial images. Thestructure of the wax at that time is in one or a few large sphericalshapes in the central binder portion, and is in the sea-island-sea shapeon the whole. However, in order for the wax to have such structure, thetype of the wax used for the binder has to be limited. Further, therehave been problems that the fixed part of the pigment in the toner hasbeen melted in the wax, and the remainder has been dispersed in thebinder, or all of the pigments are dispersed evenly in the binder; andthe charge control agent, assuming the most important role in thecharging characteristics of toners, has failed to have been located atthe outer side efficiently as well. Still further, there has remainedthe problem of excessive absorption of moisture according to theincreased amount of charging although the amount of an electric chargeon the surface of toners is increased.

In other words, in order to form high-quality pictorial images, thedevelopment of toner particles, capable of increasing the surfaceconcentration of the charge control agent in the toners irrespective tothe type of the wax and stopping the subsequent absorption of moisture,has been demanded continuously.

DISCLOSURE OF THE INVENTION

The present invention is provided with in order to more efficientlyresolve the problems of the prior art as described above.

The objects of the present invention are, therefore, to implement a highcharging effect and a high image density (I.D.) by manufacturing a corethrough suspension polymerization of binder resin monomers, molecularweight controlling agents, pigments, charge control agents, dispersionagents, anionic surfactants, waxes, polar grafting agents andhydrophilic monomers, and thus locating the charge control agents andpigments toward the surface; and to provide with highly weatherprooftoners characterized by having a double-layered structure by beingmanufactured with the further formation of a shell in the hard portionon the core in order to solve problems of long-term preservation andabsorption of moisture coming from the use of hydrophilic monomers.

Another object of the present invention is for hydrophilic polymers tohave a double-layered structure in which the outer side of toners issurrounded by the hydrophilic polymers as binder resin monomers,molecular weight controlling agents, pigments, charge control agents,dispersion agents, anionic surfactants, waxes, polar grating agents, andhydrophilic polymers are manufactured through suspension polymerization.Here, the toners have a high charging effect and image density as thepigments and charge control agents are concentrated on the hydrophilicpolymer layers forming double layers. Further, in order to solve theproblems of long-term preservation and absorption of moisture, highlyweatherproof toners characterized by having a triple-layered structureby further forming a shell in the hard portion are provided with in thepresent invention.

The present invention further provides with high-resolution and superiortoners having a single-layered structure by being manufactured throughsuspension polymerization of binder resin monomers, molecular weightcontrolling agents, pigments, charge control agents, dispersion agents,anionic surfactants, waxes, polar grafting agents, and hydrophilicmonomers.

Also, the present invention provides with high-resolution and superiortoners having a double-layered structure by being manufactured throughsuspension polymerization of binder resin monomers, molecular weightcontrolling agents, pigments, charge control agents, dispersion agents,anionic surfactants, waxes, polar grafting agents, and hydrophilicmonomers.

Still further, the present invention provides with high-resolution andhighly weatherproof toners having a double-layered structure by forminga single-layered structure through suspension polymerization of binderresin monomers, molecular weight controlling agents, pigments, chargecontrol agents, dispersion agents, anionic surfactants, waxes, polargrafting agents, and hydrophilic monomers and manufacturing a shellwhich is a rigid layer by inputting styrene monomers and cross-linkingagent on top of the single-layered structure.

Still yet further, the present invention provides with high-resolutionand highly weatherproof toners having a triple-layered structure byforming a double-layered structure through suspension polymerization ofbinder resin monomers, molecular weight controlling agents, pigments,charge control agents, dispersion agents, anionic surfactants, waxes,polar grafting agents, and hydrophilic polymers and manufacturing ashell which is a rigid layer by inputting styrene monomers andcross-linking agent on top of the single-layered structure.

The above-described hydrophilic monomer is one or more kinds ofcompounds selected from the group consisting of acrylic acid, methylmethacrylate, and acetate, and its content may be 0.1 to 20 parts byweight with respect to the total weight of the monomer mixture.

The above-described hydrophilic polymer is one or more kinds of polarpolymers selected from the group consisting of polyester-group andstyrene acrylic polymers, and its content may be 0.1 to 20 parts byweight with respect to the total weight of the monomer mixture.

The above-described polar grafting agent is one or more kinds ofcompounds selected from the group consisting of ethylene dimethacrylate,ethylene glycol dimethacrylate, diethylene glycol diacrylate,1,6-hexamethylene diacrylate, allyl methacrylate, 1,1,1-trimethylolpropane triacrylate, and triallyl amine, and its content may be 0.001 to10 parts by weight with respect to the total weight of the monomermixture.

The above-described binder resin monomer is one or more kinds ofmonomers selected from the group consisting of aromatic-vinyl-group,acrylate-group, methacrylate-group, diene-group, acidic-olefin-group,and basic-olefin-group monomers, and its content may be 0.1 to 20 partsby weight with respect to the total weight of the monomer mixture.

The above-described pigment is one or more kinds of inorganic pigmentsselected from the group consisting of metallic-powder-type,metal-oxide-type, carbon-type, sulfide-type, chromate-type, andferrocyanide-type pigments; or one or more kinds of organic pigmentsselected from the group consisting of azo-type, acidic-pigment-type,basic-pigment-type, mordant-pigment-type, phthalocyanine,quinacridone-type, and dioxane-type pigments, and its content may be 1to 100 parts by weight with respect to the total weight of the monomermixture.

The above-described charge control agent is one or more kinds ofcationic charge control agents selected from the group consisting ofnigrosine-type electron acceptor pigments, highly aliphatic metallicsalts, alkoxy amines, chelates, quarternary ammonium salts, alkylamides, fluorinated activating agents, and naphthalic acid metallicsalts; or one or more kinds of anionic charge control agents selectedfrom the group consisting of electron acceptor organic complexes,chlorinated paraffins, chlorinated polyesters, polyesters containing anexcessive amount of acids, styrene-acrylic polymers containing thesulfonyl amine of copper phthalocyanine and sulfonic acid radical, andits content may be 0.01 to 20 parts by weight with respect to the totalweight of the monomer mixture.

The above-described dispersion agent is one or more kinds of inorganicdispersion agents selected from the group consisting of calciumphosphate, magnesium salts, hydrophilic silica, hydrophobic silica, andcolloidal silica; or one or more kinds of water-soluble organic polymerdispersion agents selected from the group consisting of one or morekinds of non-ionic polymer dispersion agents selected from the groupconsisting of poly(oxyethylene) alkyl ethers, poly(oxyalkylene) alkylphenol ethers, sorbitan fatty acid esters, poly(oxyalkylene) fatty acidesters, glycerine fatty acid esters, poly(vinyl alcohols), alkylcellulose, and poly(vinyl pyrrolidone), and one or more kinds of ionicpolymer dispersion agents selected from the group consisting ofpoly(acryl amides), poly(vinyl amine), poly(vinyl amine) N-oxide,polyvinyl ammonium salts, polydialkyl diallyl ammonium salts,polyacrylic acid, polystyrene sulfonic acid, polyacrylic acid salts,polystyrene sulfonic acid salts, and polyaminoalkyl acrylic acid salts,and its content may be 0.01 to 10 parts by weight with respect to thetotal weight of the monomer mixture.

The above-described anionic surfactant is one or more kinds of compoundsselected from the group consisting of fatty acid salts, alkyl sulfuricacid ester salts, alkyl allyl sulfuric acid ester salts, dialkylsulfosuccinates, and alkyl phosphates, and its content may be 0.001 to20 parts by weight with respect to the total weight of the aqueoussolution.

The above-described wax is one or more kinds of petroleum refined waxesselected from the group consisting of paraffin waxes, microcrystallinewaxes, and ceresin waxes, or natural waxes that are carnauba waxes, orone or more kinds of synthetic waxes selected from the group consistingof polyethylene and polypropylene, and its content may be 0.01 to 30parts by weight with respect to the total weight of the monomer mixture.

The above-described molecular weight controlling agent is one or morekinds of mercaptane-group compounds selected from the group consistingof t-dodecyl mercaptane and n-dodecyl mercaptane, and its content may be0.1 to 8 parts by weight with respect to the total weight of the monomermixture.

Hereinafter, the present invention is illustrated in more detail asfollows:

In order to obtain high-quality pictorial images, when printing bylocating more than the fixed amount of a pigment on the surface of abinder, it is more efficient for obtaining a vivid-colored quality tohave the pigment come out through the shortest route rather than to havethe pigment melted in the wax located inside of the resin and come outto the surface through the long route of the resin. The difference invividness may be appreciated with naked eyes even in the color of tonerparticles in the reactor during polymerization. Also, by locating thecharge control agents as well as the pigments at the outer side of tonerparticles, it is possible to increase efficiently the amount of a chargedensity known experimentally in the past even with a small amount of thecharge control agent. Such high charge density assumes a very importantrole in the formation of a high pictorial quality when printing.Moreover, it is possible to maximize the long-term preservation andresistance to moisture of toners by forming thin layers onto them, wherethe thickness of thin layers is less than 3 μm.

In the present invention, in order to have the pigments and chargecontrol agents located on the surface of toners, besidesstyrene-acrylate-group monomers used for typical polymerized toners,hydrophilic auxiliary polymers (such as polymethyl methacrylate,polyesters, etc.) or hydrophilic monomers (such as acrylic acid,acrylate-group monomers, etc.) are used. In other words, during corepolymerization using suspension polymerization, by having thehydrophilic portion located at the outer side of the styrene-acrylatebinder resin of toners by adding a fixed amount of hydrophilic monomersor hydrophilic polymers, a large amount of the pigment and chargecontrol agent is located on the surface of toners through theinteraction among the hydrophilic portion, pigment, and charge controlagent. However, the greatest problem with the introduction of suchhydrophilic portion is that a clotting phenomenon occurs as the tonerabsorbs moisture due to the affinity to water, and eventually, the tonermay not be used when printing, if more than the fixed amount of thehydrophilic portion is inputted. Accordingly, in the present invention,in order to prevent the clotting phenomenon of toners and to improvelong-term preservation, grafting agents are introduced newly andincluded in monomers, and their thin layers within a range not harmingthe color and charge density are coated on the surface of the core whenprinting. After the core polymerization where the thin layers arecoated, a shell is formed in the hard portion by inputting monomersagain, where the formation of the shell becomes more efficient by usinggrafting agents, as a result of which the toners that are not sensitiveto moisture but can meet a high charge density and a vivid colorsimultaneously may be polymerized. If the shell is made by inputtinglipophilic monomers or polymers without using grafting agents, thinlayers are not formed readily as the monomers are diffused rapidly intothe core, and the monomers inputted later form their own new areaswithin the core. The toners provided with according to the presentinvention have a core-shell structure, and manufactured according to thesuspension polymerization method.

(1) Step of Manufacturing the Core of a Toner

In the manufacture of the core of a toner, firstly, 0.01 to 10 parts byweight of a hydrophilic dispersion agent and 0.01 to 10 parts by weightof a surfactant with respect to the weight of an aqueous solution areprepared for. Secondly, a monomer complex including 0.1 to 20 parts byweight of binder resin monomers including 30 to 90 parts by weight ofaromatic vinyl-group monomers with respect to the total weight of themonomer mixture, 5 to 70 parts by weight of one or more kinds ofmonomers selected from the group consisting of acrylate-group monomers,methacrylate-group monomers, and diene-group monomers with respect tothe total weight of the monomer mixture, and 0.1 to 20 parts by weightof an acidic or basic olefin-group monomer with respect to the totalweight of the monomer mixture; 0.1 to 20 parts by weight of ahydrophilic monomer or a hydrophilic polymer with respect to the totalweight of the monomer mixture; 0.1 to 8 parts by weight of a molecularweight controlling agent with respect to the total weight of the monomermixture; 1 to 20 parts by weight of a colored pigment with respect tothe total weight of the monomer mixture; 0.01 to 30 parts by weight of awax with respect to the total weight of the monomer mixture; 0.001 to 10parts by weight of a polar grafting agent with respect to the totalweight of the monomer mixture; 0.01 to 20 parts by weight of a chargecontrol agent with respect to the total weight of the monomer mixture;and 0.01 to 5 parts by weight of a polymerization initiator with respectto the total weight of the monomer mixture is prepared for. Then themonomer complex and the mixture which is prepared for by having 1 to 60parts by weight of the hydrophilic dispersion agent aresuspension-polymerized while adding the shearing force.

(2) Step of Formation of the Shell of a Toner

A shell is formed by inputting 1 to 30 parts by weight of astyrene-group monomer and 0 to 5 parts by weight of a cross-linkingagent to the core manufactured in the above step (1) in order tomanufacture a core-shell-structured toner.

(3) Post-Processing Step

The final toner particles are obtained by removing the dispersion agentfrom the solution containing the core-shell-structured tonermanufactured in the above step (2) in a proper method, separating thetoner by repeating the washing process and filtering process, and dryingit at a room temperature for 48 hours by using a vacuum oven. The amountof the pigment and degree of the charge density may be controlledaccording to the amounts and types of hydrophilic monomers and polymersinputted.

In the above, for monomers, one or more kinds of monomers selected fromthe group consisting of aromatic vinyl-group and acrylate-group,methacrylate-group, and diene-group monomers are used, and selectively,acidic or basic olefin-group monomers may be used.

The above-described aromatic vinyl-group monomers include styrene,monochlorostyrene, methylstyrene, dimethylstyrene, etc., that can beused singly or mixed with one or more kinds of such compounds. It ispreferable to use 30 to 90 parts by weight of an aromatic vinyl-groupmonomer with respect to the total weight of the monomer mixture. Thereason for limiting the content of an aromatic vinyl-group monomer to 30to 90 parts by weight is to adjust Tg of the polymerized toner.Generally, if less than 30 parts by weight of the aromatic vinyl-groupmonomer is used, Tg of the toner is too low, the toner is attached tothe fusing roller during printing, and therefore, problems such as hotoffset, etc. may occur; and if greater than 90 parts by weight of suchmonomer is used, Tg of the toner becomes too high, the toner is notmelted sufficiently during printing, and therefore, the problem ofgreatly lowering settling on sheets of paper may occur.

The above-described acrylate-group monomers include methyl acrylate,ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate,2-ethylhexyl acrylate, etc.; methacrylate-group monomers include methylmethacrylate, ethyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, etc.; anddiene-group monomers include butadiene, isoprene, etc., which may beused singly or mixed with one or more kinds of such compounds. It ispreferable to use 5 to 70 parts by weight of the above monomer withrespect to the total weight of the monomer mixture. As mentioned in theabove, the reason for limiting the weight of the monomer to 5 to 70parts by weight is to prevent the problems that may occur duringprinting by adjusting Tg of the toner to a proper level.

The above-described acidic olefin-group monomers include α- orβ-ethylene compounds having carboxylic radicals, etc.; and basicolefin-group monomers include methacrylic acid esters, methacryl amides,vinyl amine, and diallyl amines of aliphatic alcohols, their ammoniumsalts, etc. having amine radicals or quarternary ammonium radicals,which may be used singly or mixed with one or more kinds of suchcompounds. It is preferable to use 0.1 to 20 parts by weight of theabove-described acidic olefin-group monomer or basic olefin-groupmonomer with respect to the total weight of the monomer mixture. Theacidic or basic olefin-group monomer is added in order to improve thecharging characteristic of the surface. However, if its content exceeds20 parts by weight, it has a negative affect on the reaction stabilityduring the polymerization of the toner and a large amount of coagulum isgenerated after polymerization.

The above-described hydrophilic monomers include acrylic acid, methylmethacrylate, acetate, etc., which may be used singly or mixed with oneor more kinds of such compounds. It is preferable to use 0.1 to 20 partsby weight of the above hydrophilic monomer with respect to the totalweight of the monomer mixture. If its content is less than 0.1 part byweight, the desired effect, i.e., effective positioning of the chargecontrol agents and pigments on the surface of the toner is failed; if itexceeds 20 parts by weight, the reaction stability is lowered insuspension polymerization which is reacted in water.

The above-described hydrophilic polymers include polyesters, styreneacryls, etc., which may be used singly or mixed with one or more kindsof such compounds. It is preferable to use 0.1 to 20 parts by weight ofthe above hydrophilic polymer with respect to the total weight of themonomer mixture. If the content of the hydrophilic polymer is less than0.1 parts by weight, it is not possible for the hydrophilic polymer toform the polymer layer on the surface of the toner efficiently; if itexceeds 20 parts by weight, the reaction stability is disturbed as thephase separation occurs during polymerization.

It is possible to use oily initiators and aqueous initiators for theabove-described polymerization initiators. Their concrete examplesinclude azo-group initiators such as bis-isobutyronitrile,azobisdimethyl valeronitrile, etc.; organic peroxides such as benzoylperoxide, lauroyl peroxide, etc.; and usual aqueous initiators such aspotassium persulfate, ammonium persulfate, etc. It is preferable to use0.01 to 5 parts by weight of a polymerization initiator with respect tothe total weight of the monomer mixture. If its content is less than0.01 parts by weight, there remain unreacted materials; if it exceeds 5parts by weight, the reaction speed is too fast and the reactionstability is lowered.

Mercaptane-group compounds such as dodecyl mercaptane, n-dodecylmercaptane, etc. may be used for the above-described molecular weightcontrolling agents, which may be used singly or mixed with one or morekinds of such compounds. It is preferable to use 0.1 to 8 parts byweight of the above-described molecular weight controlling agent withrespect to the total weight of the monomer mixture. A molecular weightcontrolling agent is added in order to further improve settling of thetoner during printing by lowering the molecular weight, but may not beadded, if necessary. If its content exceeds 8 parts by weight, themolecular weight becomes very small and hot offset occurs duringprinting.

The above-described pigments include inorganic pigments such asmetallic-powder-type pigments, and metal-oxide-type, carbon-type,sulfide-type, chromate-type, ferrocyanide-type pigments; and organicpigments such as azo-type, acidic-pigment-type, basic-pigment-type,mordant-pigment-type, phthalocyanine, quinacridone-type, anddioxane-type pigments, which may be used singly or combined with one ormore kinds of such compounds. It is preferable to use 1 to 20 parts byweight of the above-described pigment with respect to the total weightof the monomer mixture. If the content of the pigment is less than 1part by weight, it is not possible to implement the desired colorsufficiently; if it exceeds 20 parts by weight, it is difficult for themonomer and pigment to be diffused.

The above-described charge control agents include cationic chargecontrol agents such as nigrosine-type electron acceptor pigments, highlyaliphatic metallic salts, alkoxy amines, chelates, quarternary ammoniumsalts, alkyl amides, fluorinated activating agents, metallic salts ofnaphthalic acid, etc.; or anionic charge control agents such as electronacceptor organic complexes, fluorinated paraffins, fluorinatedpolyesters, polyesters containing an excessive amount of acids, sulfonylamine of copper phthalocyanine, styrene-acryl-group polymers includingsulfonic acid radicals, etc., which may be used singly or mixed with oneor more kinds of such compounds. It is preferable to use 0.01 to 20parts by weight of the above-described charge control agent with respectto the total weight of the monomer mixture. If its content is less than0.01 parts by weight, it is not possible to have a sufficient chargedensity which is necessary for printing; if it exceeds 20 parts byweight, an unnecessarily high charge density is obtained and thepictorial quality is lowered during printing.

The above-described dispersion agents include inorganic dispersionagents, water-soluble organic polymer dispersion agents, etc. Concreteexamples of inorganic dispersion agents include calcium phosphate,magnesium salts, hydrophilic silica, hydrophobic silica, colloidalsilica, etc.; of water-soluble organic non-ionic polymer dispersionagents include poly(oxyethylene) alkyl ether, poly(oxyalkylene) alkylphenol ether, sorbitan fatty acid ester, poly(oxyalkylene) fatty acidester, glycerine fatty acid ester, poly(vinyl alcohols), alkylcellulose, poly(vinyl pyrrolidone), etc.; and of water-soluble organicionic polymer dispersion agents include poly(acryl amides), poly(vinylamine), poly(vinyl amine) N-oxide, polyvinyl ammonium salts, polydialkyldiallyl ammonium slats, polyacrylic acid, polystyrene sulfonic acid,polyacrylic acid salts, polystyrene sulfonic acid salts, polyaminoalkylacrylic acid salts, etc. The above-described dispersion agents may beused singly or mixed with one or more kinds of such compounds. It ispreferable to use 0.01 to 10 parts by weight of the above-describeddispersion agent with respect to the total weight of the aqueoussolution. If its content is less than 0.1 parts by weight, the reactionstability is disturbed during suspension polymerization; if it exceeds10 parts by weight, the formation of unnecessary side-reaction materials(emulsion particles) is increased and the sizes of toner particles maybecome smaller than those to be implemented.

The above-described anionic surfactants include fatty acid salts, alkylsulfuric acid ester salts, alkyl allyl sulfuric acid ester salts,dialkyl sulfosuccinates, alkyl phosphates, etc., which may be usedsingly or mixed with one or more kinds of such compounds. It ispreferable to use 0.001 to 20 parts by weight of the above-describedanionic surfactant with respect to the total weight of the aqueoussolution. If its content is less than 0.001 parts by weight, thereaction stability is disturbed during suspension polymerization; if itexceeds 20 parts by weight, the formation of unnecessary side-reactionmaterials (emulsion particles) is increased and the sizes of tonerparticles may become smaller than those to be implemented.

The above-described polar grafting agents include ethylenedimethacrylate, ethylene glycol dimethacrylate, diethylene glycoldiacrylate, 1,6-hexamethylene diacrylate, allyl methacrylate,1,1,1-trimethylol propane triacrylate, triallyl amine, etc., which maybe used singly or mixed with one or more kinds of such compounds. It ispreferable to use 0.001 to 10 parts by weight of the above-describedpolar grafting agent with respect to the total weight of monomers. Ifits content is less than 0.001 parts by weight, it is not possible toform the shell of a hard portion made on the core; if it exceeds 10parts by weight, the gelation of the core is over-done and settling ofthe toner is lowered during printing.

The above-described waxes include but are not limited specially topetroleum refined waxes, natural waxes, and synthetic waxes. Concreteexamples of petroleum refined waxes include paraffin waxes,microcrystalline waxes, ceresin waxes, of natural waxes include carnaubawaxes, etc. and of synthetic waxes include polyethylene, polypropylene,etc., which may be used singly or mixed with one or more kinds of suchcompounds. It is preferable to use 0.01 to 30 parts by weight of theabove-described wax with respect to the total weight of monomers. If itscontent is less than 0.01 parts by weight, settling during printing andspreading of the wax on the surface of the toner are lowered; and if itexceeds 30 parts by weight, the reaction stability is lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects, and advantages will be betterunderstood from the following detailed description of preferredembodiments of the invention with reference to the drawings, in which:

FIG. 1 is an approximate diagram showing toner particles having adouble-layered structure according to the present invention;

FIG. 2 is an approximate diagram showing toner particles having atriple-layered structure according to the present invention;

FIG. 3 is a graph showing the result of measurement of the size of tonerparticles manufactured in Preferred Embodiments 1 to 4 and ComparativeExamples 1 and 2 using a multisizer Coulter counter; and

FIG. 4 is a photograph showing the result of measurement of the shape oftoner particles manufactured in Preferred Embodiments 2 to 4 andComparative Examples 3 to 5.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is illustrated in more detail through thefollowing preferred embodiments:

Preferred Embodiment 1 Manufacture of the Single-Layered Toner UsingHydrophilic Monomers and Polar Grafting Agents

(1) Step of Manufacture of the Core of a Toner

10 g portion of polyvinyl alcohol and 1 g of dodecyl benzene sulfuricacid ester sodium salt were put into a 500-ml volumetric flask andmelted with 400 g of distilled water in order to prepare for an aqueoussolution, and heated to 70° C. which was a reaction temperature.

Also, 160 g of styrene, 36 g of butyl acrylate, 4 g of acrylic acid, 4 gof allyl methacrylate, 0.02 g of n-dodecyl mercaptane, and 10 g of cyanpigment were put into another container, and mixed at a speed of 2,000rpm for 2 hours with a bead mill, after which 105 g of the monomermixture was prepared for by removing the beads. The mixture thusprepared for was put into another container, and mixed at a speed of2,000 rpm for 2 hours with a bead mill, after which 105 g of the monomermixture was prepared for by removing the beads. The mixture thusprepared for was put into the water of 70° C., heated, mixed with 1 g ofa styrene-acryl-group polymer charge control agent containing sulfonicacid radicals and 5 g of a paraffin wax for 20 minutes, and meltedsufficiently. To the monomer mixture melted sufficiently, 2 g ofazobisisobutyronitrile, which was a polymerization initiator, was put,and mixed for 5 minutes in order to prepare for a reaction material.

The reaction material was put into the aqueous solution prepared for inthe above, and the reaction was continued while mixing at a speed of10,000 rpm with a homogenizer for 20 minutes. After 20 minutes, the corewas manufactured by mixing with a general mixer at a speed of 600 rpmfor 15 hours.

(2) Post-Processing Step

A toner was manufactured by repeating sufficient washing and filteringof the final toner with water in order to remove the dispersion agentand vacuum drying.

Preferred Embodiment 2 Manufacture of a Double-Layered Toner UsingHydrophilic Monomers and Polar Grafting Gents

(1) Step of Manufacture of the Core of a Toner

10 g portion of polyvinyl alcohol and 1 g of dodecyl benzene sulfuricacid ester sodium salt were put into a 500-ml volumetric flask andmelted with 400 g of distilled water in order to prepare for an aqueoussolution, and heated to 70° C. which was a reaction temperature.

Also, 160 g of styrene, 36 g of butyl acrylate, 4 g of acrylic acid, 4 gof allyl methacrylate, 0.02 g of n-dodecyl mercaptane, and 10 g of cyanpigment were put into another container, and mixed at a speed of 2,000rpm for 2 hours with a bead mill, after which 105 g of the monomermixture was prepared for by removing the beads. The mixture thusprepared for was put into the water of 70° C., heated, mixed with 1 g ofa styrene-acryl-group polymer charge control agent containing sulfonicacid radicals and 5 g of a paraffin wax for 20 minutes, and meltedsufficiently. To the monomer mixture melted sufficiently, 2 g ofazobisisobutyronitrile, which was a polymerization initiator, was put,and mixed for 5 minutes in order to prepare for a reaction material.

The reaction material was put into the aqueous solution prepared for inthe above, and the reaction was continued while mixing at a speed of10,000 rpm with a homogenizer for 20 minutes. After 20 minutes, the corewas manufactured by mixing with a general mixer at a speed of 600 rpmfor 15 hours.

(2) Step of the Formation of the Shell of the Toner

The final toner was manufactured by forming a shell y putting and mixingthe core manufactured in the above Step (1), 20 g of styrene as amonomer, 0.12 g of divinyl benzene as a cross-linking agent, and 0.4 gof azobisisobutyronitrile as a polymerization initiator into a 500-mlvolumetric flask.

(3) Post-Processing Step

A toner was manufactured by repeating sufficient washing and filteringof the final toner with water in order to remove the dispersion agentsand vacuum drying.

Preferred Embodiment 3 Manufacture of a Double-Layered Toner UsingHydrophilic Polymers and Polar Grafting Agents

(1) Step of Manufacture of the Core of a Toner

10 g portion of colloidal silica was dispersed with 400 g of distilledwater in a 500-ml volumetric flask in order to prepare for an aqueoussolution, and heated to 70° C. which was a reaction temperature.

Also, 160 g of styrene, 36 g of butyl acrylate, 4 g of allylmethacrylate, 0.02 g of n-dodecyl mercaptane, 8 g of polyester, and 10 gof cyan pigment were put into another container, and mixed at a speed of2,000 rpm for 2 hours with a bead mill, after which 105 g of the monomermixture was prepared for by removing the beads. The mixture thusprepared for was put into the water of 70° C., heated, mixed with 1 g ofa styrene-acryl-group polymer charge control agent containing sulfonicacid radicals and 5 g of a paraffin wax for 20 minutes, and meltedsufficiently. To the monomer mixture melted sufficiently, 2 g ofazobisisobutyronitrile, which was a polymerization initiator, was put,and mixed for 5 minutes in order to prepare for a reaction material.

The reaction material was put into the aqueous solution prepared for inthe above, and the reaction was continued while mixing at a speed of10,000 rpm with a homogenizer for 20 minutes. After 20 minutes, the corewas manufactured by mixing with a general mixer at a speed of 600 rpmfor 15 hours.

(2) Post-Processing Step

A toner was manufactured by repeating sufficient washing and filteringof the final toner with water in order to remove the dispersion agentsand vacuum drying.

Preferred Embodiment 4 Manufacture of a Triple-Layered Toner Using PolarGrafting Agents and Hydrophilic Polymers

(1) Step of Manufacture of the Core of a Toner

10 g portion of colloidal silica was dispersed with 400 g of distilledwater in a 500-ml volumetric flask in order to prepare for an aqueoussolution, and heated to 70° C. which was a reaction temperature.

Also, 160 g of styrene, 36 g of butyl acrylate, 4 g of allylmethacrylate, 0.02 g of n-dodecyl mercaptane, 8 g of polyester, and 10 gof cyan pigment were put into another container, and mixed at a speed of2,000 rpm for 2 hours with a bead mill, after which 105 g of the monomermixture was prepared for by removing the beads. The mixture thusprepared for was put into the water of 70° C., heated, mixed with 1 g ofa styrene-acryl-group polymer charge control agent containing sulfonicacid radicals and 5 g of a paraffin wax for 20 minutes, and meltedsufficiently. To the monomer mixture melted sufficiently, 2 g ofazobisisobutyronitrile, which was a polymerization initiator, was put,and mixed for 5 minutes in order to prepare for a reaction material.

The reaction material was put into the aqueous solution prepared for inthe above, and the reaction is continued while mixing at a speed of10,000 rpm with a homogenizer for 20 minutes. After 20 minutes, the coreis manufactured by mixing with a general mixer at a speed of 600 rpm for15 hours.

(2) Step of the Formation of the Shell of the Toner

The final toner was manufactured by forming a shell by putting andmixing the core manufactured in the above Step (1), 20 g of styrene as amonomer, 0.12 g of divinyl benzene as a cross-linking agent, and 0.4 gof azobisisobutyronitrile as a polymerization initiator into a 500-mlvolumetric flask.

(3) Post-Processing Step

A toner was manufactured by repeating sufficient washing and filteringof the final toner with water in order to remove the dispersion agentsand vacuum drying.

Comparative Example 1 Manufacture of a Single-Layered Toner not UsingHydrophilic Monomers and Hydrophilic Polymers

A toner was manufactured in the same method as that in PreferredEmbodiment 1 or 3 except that hydrophilic monomers and hydrophilicpolymers were not added.

Comparative Example 2 Manufacture of a Double-Layered Toner not UsingHydrophilic Monomers and Hydrophilic Polymers

A toner was manufactured in the same method as that in PreferredEmbodiment 2 or 4 except that hydrophilic monomers and hydrophilicpolymers were not added.

Comparative Example 3 Manufacture of a Double-Layered Toner not UsingPolar Grafting Agents

A toner was manufactured in the same method as that in PreferredEmbodiment 2 except that polar grafting agents were not added.

Comparative Example 4 Manufacture of a Triple-Layered Toner not UsingPolar Grafting Agents

A toner was manufactured in the same method as that in PreferredEmbodiment 4 except that polar grafting agents are not added.

Comparative Example 5 Manufacture of a Double-Layered Toner not UsingHydrophilic Monomers, Hydrophilic Polymers, and Polar Grafting Agents

A toner was manufactured in the same method as that in PreferredEmbodiment 2 or 4 except that hydrophilic monomers and hydrophilicpolymers were not added.

Testing Example 1 Measurement of the Sizes of Toner Particles

The sizes of toner particles manufactured in Preferred Embodiments 1 to4 and Comparative Examples 1 and 2 were measured by using a multisizerCoulter counter, of which results were shown in FIG. 3.

As seen in the graph of FIG. 3, if hydrophilic monomers of PreferredEmbodiment 1 were added, toner particles generally have a size of about6.1 micrometers, which was the same as that of the case in which nohydrophilic monomers in Comparative Example 1 were added. It wasbecause, in case of hydrophilic monomers, co-polymers were formedrandomly with other monomers at the outer side of particles duringpolymerization, and thus, the particle sizes were not affected greatly.Here, it was seen that the sizes were increased to 6.1 to 7.2micrometers (??) if a shell was made in the rigid layer, which impliesthat the double-layered structure was formed successfully.

It was also seen that, if hydrophilic polymers were added, the sizes oftoner particles were increased to 6.1 to 6.5 micrometers compared to thecase that hydrophilic monomers were used. It was because hydrophilicpolymers form thin layers at the outer side of particles afterpolymerization. Further, if a shell of the hard portion was made onceagain to improve weatherability, the sizes were increased to 6.5 to 7.5micrometers, which implied that another layer was formed over thehydrophilic polymers.

Testing Example 2 Measurement of the Shapes of Toner Particles

The shapes of toner particles manufactured in Preferred Embodiments 2 to4 and Comparative Examples 3 to 5 were measured by using a scanningelectron microscope (SEM). The results of measurement were shown in FIG.4.

As seen in the SEM photograph of FIG. 4(a), in cases of PreferredEmbodiments 2 to 4 in which a shell in the hard portion was made byusing polar grafting agents, toner particles were spherical particleshaving the surface with almost no curves. This was the same in PreferredEmbodiment 1 and Comparative Examples 1 and 2. However, it was difficultto find out whether the layers were formed from SEM, and whether thelayers were formed may be known indirectly through the difference insizes mentioned in the above.

According to the SEM photograph of FIG. 4(b), in case of PreferredEmbodiment 3 in which hydrophilic polymers were added, the surface ofparticles was shown to be curved contrary to the previous case. Here, itwas seen indirectly that hydrophilic polymers form new layers at theouter side of the toner.

As seen in the SEM photograph of FIG. 4(c), if a shell of the hard layerwas made without adding polar grafting agents, light and darkness wereshown as seen in the photograph. Here, the black portion was a domaincreated when the styrene-group monomer inputted in order to form theshell fail to form the layer efficiently but was diffused into therelatively non-polar core.

The approximate double-layered structure of the toner according toPreferred Embodiment 2 was as shown in FIG. 1, where the first layer (4)of toner particles was a soft layer, over which surface the pigment andcharge control agent were gathered; and the second layer (5) was a rigidlayer, over which a thin shell was formed. And an approximatetriple-layered structure of the toner according to Preferred Embodiment4 was as shown in FIG. 2, where the second layer (2) was a polar polymerlayer, over which the pigment and charge control agent were gathered;and the second layer (3) was a rigid layer over which a thin shell isformed.

Testing Example 3 Measurement of the Amount of Charging and ImageConcentration

The toners manufactured in Preferred Embodiments 1 through 4 andComparative Examples 1 through 5 were mixed with 2 parts by weight ofsurface-processed silica RY200S, and stirred in a blender at a speed of3,000 rpm for 3 minutes in order to process the surface. Their amountsof charging were measured in the suction method in an HP4500 printer, ofwhich results were shown in Table 1 below; and the image concentrationsof sheets of paper printed were measured, of which results were alsoshown in Table 1 below: TABLE 1 Amount of charging Image Sample number(μC/g) concentration Preferred Embodiment 1 −50 1.5 Preferred Embodiment2 −46 1.5 Preferred Embodiment 3 −54 1.5 Preferred Embodiment 4 −49 1.5Comparative Example 1 −21 1.3 Comparative Example 2 −19 1.3 ComparativeExample 3 −48 1.4 Comparative Example 4 −44 1.4 Comparative Example 5−19 1.3

As shown in the above Table 1, in view of Preferred Embodiments 1 and 2of the present invention, the affect of the formation of a hard shell atthe outer side of particles on the amount of charging of the toners isvery insignificant. However, it is seen that Comparative Example 1, inwhich no hydrophilic monomers or hydrophilic polymers are put into, haslow amount of charging and image concentration values compared toPreferred Embodiments 1 to 3, in which hydrophilic monomers andhydrophilic polymers are put into. It is seen from the above resultsthat the addition of hydrophilic monomers and hydrophilic polymers has agreat affect on the amount of charging and color concentration of thetoners, but the rigid layered structure at the outermost side is notgreatly related to the amount of charging and color concentration of thetoners.

Testing Example 4 Measurement of Waterproofing and Weatherability ofToners

In order to study how affective the shell portion forming the outermostside of the toner is on moisture and temperature, thermohydrostaticexperiments were performed. In the pyrohumid test (30° C./RH 80%),cartridges were put into a thermohydrostat and left for about 10 hoursto allow saturation. Thereafter, a printer was put into athermohydrostat in order to perform the 100-sheet short-term test, andwaste, Q/M, and printing efficiency were measured. All of PCR wascleaned before and after the pyrohumid evaluation. TABLE 2 Amount ofconsumption Rate of printing (g) (%) Preferred Embodiment 4.2 73 1Preferred Embodiment 2.1 94 2 Preferred Embodiment 4.5 70 3 PreferredEmbodiment 2.4 91 4 Comparative Example 3.6 82 1 Comparative Example 2.491 2 Comparative Example 4.0 76 3 Comparative Example 4.1 75 4Comparative Example 4.7 69 5

As shown in the above Table 2, it is seen that, in Preferred Embodiments1 and 3 having no rigid-shell structure, compared to PreferredEmbodiments 2 and 4 having a rigid-shell structure, the toner is notprinted to sheets of paper during printing, the amount of waste remainedin cartridges is very large, and the printing rate is lowered greatly.In other words, it is seen that the toner is less sensitive to moistureand temperature as there exists the non-polar shell layer. It is alsoseen that, in Preferred Embodiments 1 to 3 having hydrophilic monomersor polymers, compared to Comparative Example 1 having no hydrophilicmonomers or polymers relatively, the amount of waste and printing rateare lowered. It seems to be that the toner becomes more sensitive tomoisture as hydrophilic monomers or hydrophilic polymers are put intothe toner. Therefore, in order to manufacture a weatherproof toner thatis tolerant to moisture or temperature change, the outermost side of thetoner should be equipped with a rigid-shell structure.

As illustrated in the above, the present invention is a useful inventionin that it provides with toners that can prevent entangling due tomoisture as the double or triple layers are included and improveweatherability.

While certain present preferred embodiments of the invention have beenshown and described, it is to be distinctly understood that theinvention is not limited thereto but may be otherwise variously embodiedand practiced within the scope of the following claims:

1. A toner having a single-layered structure as said toner ismanufactured through the suspension polymerization of binder resinmonomers, molecular weight controlling agents, pigments, charge controlagents, dispersion agents, anionic surfactants, waxes, polar graftingagents, and hydrophilic monomers.
 2. A toner having a double-layeredstructure as said toner is manufactured through the suspensionpolymerization of binder resin monomers, molecular weight controllingagents, pigments, charge control agents, dispersion agents, anionicsurfactants, waxes, polar grafting agents, and hydrophilic polymers. 3.A toner having a double-layered structure by forming a single-layeredstructure through the suspension polymerization of binder resinmonomers, molecular weight controlling agents, pigments, charge controlagents, dispersion agents, anionic surfactants, waxes, polar graftingagents, and hydrophilic monomers, and further manufacturing a shell,which is a rigid layer, by inputting a styrene-group monomer and across-linking agent over said single-layered structure.
 4. A tonerhaving a triple-layered structure by forming a double-layered structurethrough the suspension polymerization of binder resin monomers,molecular weight controlling agents, pigments, charge control agents,dispersion agents, anionic surfactants, waxes, polar grafting agents,and hydrophilic polymers, and further manufacturing a shell, which is arigid layer, by inputting a styrene-group monomer and a cross-linkingagent over said single-layered structure.
 5. The toner according toclaim 1 or 3, wherein said hydrophilic monomers are one or more kinds ofcompounds selected from the group consisting of acrylic acid, methylmethacrylate, and acetate; and the content of said hydrophilic monomeris 0.1 to 20 parts by weight with respect to the total weight of themonomer mixture.
 6. The toner according to claim 2 or 4, wherein saidhydrophilic polymers are one or more kinds of polar polymers selectedfrom the group consisting of polyester-group and styrene-acryl-grouppolymers; and the content of said hydrophilic polymers is 0.1 to 20parts by weight with respect to the total weight of the monomer mixture.7. The toner according to any of claims 1 through 4, wherein said polargrafting agents are one or more kinds of compounds selected from thegroup consisting of ethylene dimethacrylate, ethylene glycoldimethacrylate, diethylene glycol diacrylate, 1,6-hexamethylenediacrylate, allyl methacrylate, 1,1,1-trimethylol propane triacrylate,and triallyl amine; and the content of said polar grafting agents is0.001 to 10 parts by weight with respect to the total weight of themonomer mixture.
 8. The toner according to any of claims 1 through 4,wherein said binder resin monomers are one or more kinds of compoundsselected from the group consisting of aromatic-vinyl-group,acrylate-group, methacrylate-group, diene-group, acidic-olefin-group,and basic-olefin-group monomers; and the content of said binder resinmonomers is 0.1 to 20 parts by weight with respect to the total weightof the monomer mixture.
 9. The toner according to any of claims 1through 4, wherein: said pigments are one or more kinds of inorganicpigments selected from the group consisting of metallic-powder-type,metal-oxide-type, carbon-type, sulfide-type, chrome-salt-type, andferrocyanide-type pigments; or one or more kinds of organic pigmentsselected from the group consisting of azo-type, acidic-pigment-type,basic-pigment-type, mordant-pigment-type, phthalocyaniquinacridone-type,and dioxane-type pigments; and the content of said pigments is 1 to 20parts by weight with respect to the total weight of the monomer mixture.10. The toner according to any of claims 1 through 4, wherein: saidcharge control agents are one or more kinds of cationic charge controlagents selected from the group consisting of nigrosine-type electronacceptor pigments, highly aliphatic metallic salts, alkoxy amines,chelates, quarternary ammonium salts, alkyl amides, fluorinatedactivation agents, and metallic salts of naphthalic acid; or one or morekinds of anionic charge control agents selected from the groupconsisting of electron acceptor organic complexes, chlorinatedparaffins, chlorinated polyesters, polyesters containing an excessiveamount of acids, sulfonyl amine of copper phthalocyanine, andstyrene-acryl-group polymers including sulfonic acid radicals; and thecontent of said charge control agents is 0.01 to 20 parts by weight withrespect to the total weight of the monomer mixture.
 11. The toneraccording to any of claims 1 through 4, wherein: said dispersion agentsare one or more kinds of inorganic dispersion agents selected from thegroup consisted of calcium phosphates, magnesium salts, hydrophilicsilica, hydrophobic silica, and colloidal silica; or one or more kindsof water-soluble organic polymer dispersion agents selected from thegroup consisting of one or more kinds of non-ionic polymer dispersionagents selected from the group consisting of poly(oxyethylene) alkylethers, poly(oxyalkylene) alkyl phenol ethers, sorbitan fatty acidesters, poly(oxyalkylene) fatty acid esters, glycerine fatty acidesters, poly(vinyl alcohols), alkyl cellulose, and poly(vinylpyrrolidone); and one or more kinds of ionic polymer dispersion agentsselected from the group consisting of poly(acryl amides), poly(vinylamine), poly(vinyl amine) N-oxide, polyvinyl ammonium salt,polydialkyldiallyl ammonium slats, polyacrylic acid, polystyrenesulfonic acid, polyacrylic acid salt, polystyrene sulfonic acid salt,and polyaminoalkyl acrylic acid salts; and the content of saiddispersion agents is 0.01 to 10 parts by weight with respect to thetotal weight of the monomer mixture.
 12. The toner according to any ofclaims 1 through 4, wherein said anionic surfactants are one or morekinds of compounds selected from the group consisting of fatty acidsalts, alkyl sulfuric acid ester salts, alkylallyl sulfuric acid estersalts, dialkyl sulfosuccinates, and alkyl phosphates; and the content ofsaid anionic surfactants is 0.001 to 20 parts by weight with respect tothe total weight of the aqueous solution.
 13. The toner according to anyof claims 1 through 4, wherein: said waxes are one or more kinds ofpetroleum refined waxes selected from the group consisting of paraffinwaxes, microcrystalline waxes, and ceresin wax; natural wax which is thecarnauba wax; or one or more kinds of synthetic waxes selected from thegroup consisting of polyethylene and polypropylene; and the content ofsaid waxes is 0.01 to 30 parts by weight with respect to the totalweight of the monomer mixture.
 14. The toner according to any of claims1 through 4, wherein said molecular weight controlling agents are one ormore kinds of mercaptane-group compounds selected from the groupconsisting of t-dodecyl mercaptane and n-dodecyl mercaptane; and thecontent of said molecular weight controlling agents is 0.1 to 8 parts byweight with respect to the total weight of the monomer mixture.
 15. Thetoner according to claim 3 or 4, wherein the content of saidstyrene-group monomer and the content of said cross-linking agent are 1to 30 parts by weight and 0 to 5 parts by weight, respectively.